In the process of recovering rare earth elements (REE) from waste rare earth luminescent materials, the methods are researching for the higher recovery rate. But the blue, green phosphor in rare earth luminescent materials were aluminum and magnesium salts which are stable structure. The method of direct acid hydrolysis failed to leach REE effectively, which greatly affects the recovery of rare earth recycling and the development of industrial and result in a waste of valuable rare earth resources.
Currently, the Chinese patent (application number: 200810029417.5) discloses a method of recovering REE from waste fluorescent lamps. By alkaline fusion, the waste rare earth phosphor was directly mixed with alkali and roasted. After blue and green phosphors were decomposed, acid hydrolysis and extraction were used to recycling REE. This approach improved the leaching rate of the REE. This approach improved the leaching rate of the REE. But it caused a large number of unnecessary waste of energy and the alkali consumption, while the non-rare earth elements such as Ca, Mg, Ba, etc., are not reasonably separated from REE, resulting in low efficiency of extraction solvent afterwards. By this patented method, Y, Eu, Tb and Y were leached efficiently step by step, and were preliminarily separated and enriched.
Compared with the prior art, there are some advantages of dual hydrochloric in the present invention as followed: (1) higher REE leach rate; (2) the non-rare earth elements and REE are effectively separated, more easily control to separate and enrich the REE, less extraction pressure in the follow-up process; (3) obvious energy saving effect, more than 50% alkali reduced, less post-extraction drug consumption, and less recovery cost.